turbo 318

There are ways to put a turbo in correctly cheaper then you may see in Hot Rod magazine, but not cheap in general.

Figure on spending at least 500$ on a good used turbo, a new turbo in the size you need is probably going to run at least 800$ and can be as much as 3000$ or more if it is a better brand name, has ball bearings, has better turbine materials, etc .

You need manifolds, there is a way to mount headers backwards or use a set of shortie truck headers. You can then fab your own exhaust tubing into the turbo, then out to the side or back of the car. If you already have a welder, welding skills, a saw, etc, you could buy headers, a flange, tubing, etc and do it for around 500-1000$. You would also need to put a wastegate (WG) between the turbo and the headers and route the waste either into the after-turbo exhaust or into the atmosphere. A new WG is 300-600+$ and you could probably get a used one for 200$.

You then need a pile of aluminum tubing, silicone couplers, an intercooler (IC), and a blow off valve (BOV). Figure about 200-1000$ for the IC and 200$ or more for a BOV.

You will need a blow-through carb or a fuel injection set up. Megasquirt (MS) is a cheap fuel injection system, but you need tuning skills, a wideband (WB) air/fuel meter, injectors, and a pile of sensors. Figure about 1500$ or more for a MS fuel injection system. A carb is going to be 500$ or more. You should have at least a WB and exhaust EGT gauge when running a turbo. They will keep you safe. An engine under boost in a lean condition will melt.

Then you will need a bunch of random stuff like gaskets, vacuum hose, etc.

I'd guess, if you sourced everything used and fabbed up everything on your own, you could turbo a V-8 for 2000-2500$. This would include a WB and EGT gauge. Again, you would need to have very good Ebay skills to find stuff used and cheap. You would also need fabrication skills for the headers and tubing. This is just my estimate to put a turbo on your engine. This does not include modifying the engine, trans, rear end in any way.

And if I missed something, I am on pain killers for a recent surgery.

Lastly, a stock 318 is not going to hold together very long with a huge turbo and lots of boost. A smaller turbo that spools quickly will be a lot more fun to drive on the street anyway.